The present invention relates to accordion storm shutters and, more particularly, to transparent blades of aluminum and plastic for accordion storm shutters to protect glass windows and doors in homes, office buildings and other walled structures from the destructive force of storm systems, such as hurricanes.
Violent storms are natural phenomena that often generate winds having the potential for destruction of property and life. This potential is evidenced upon review of the storm systems known as Hurricane Hugo and Hurricane Andrew that struck the eastern coast of the United States. Hurricane Andrew was especially destructive taxing the entire nation in the form of rebuilding costs and insurance rates. In light of the escalating costs for rebuilding, home owners, business owners and insurance companies alike have a common goal in protecting property. Proper shuttering of windows and doors, typically the weakest portion of a structure, has become a necessity if the structure""s contents are to be protected.
The study of storms has determined that storm shutters must withstand more than just high winds. In reality the majority of the destruction is a direct result of impacts by debris carried by these high winds. In an effort to reduce the destructive effect of such windborne debris, changes to the building codes in areas frequently subjected to these type storm systems have been made, notably first in South Florida, then throughout Florida with the introduction of the new State of Florida Building Code, then the southeast coastal states with the new Southern Building Congress Code SSTD 12-99 and next internationally, with the International Building Code due to be released next year. One change made included in all these codes require that storm shutters withstand a large missile impact test. Testing is performed by projecting a large object, such as a length of two by four lumber, at a velocity of 50 feet per second or higher, against the storm shutter being tested. This is intended to simulate the impact of windborne debris in a hurricane or similar storm. To successfully pass, the shutter must remain intact after the projectile has impacted it.
Along with providing protection from such windborne debris, it has been found desirable for storm shutters to be constructed of translucent materials so as not to nullify the main purpose of transparent glass windows and doors, especially when the electricity has been lost in a storm. The transparent materials prevent claustrophobic tendencies of occupants secured within the structure yet permits law enforcement officials to inspect shuttered structures.
A number of U.S. Patent numbers, notably U.S. Pat. No. 4,685,261, 4,175,357, 5,228,238 and 5,457,921, disclose various types of translucent storm shutter assemblies having a transparent panel constructed of flat plastic such as polycarbonate and mounted in a frame of aluminum or steel or a corrugated plastic such as polycarbonate reinforced with aluminum or steel. The plastic sheet used in the ""261 and ""357 patents is firmly secured to a frame with little if any allowance for expansion and contraction relative to the frame. Such restriction can cause the shutter assembly to become damaged even without exposure to storms. The plastic sheet used in the ""238 patent, on the other hand, is mounted to its frame so as to allow each sheet relative freedom to expand and contract. As taught by the ""238 patent, this problem may be avoided by mounting each plastic sheet in a frame so that it is relatively unrestricted and free to change in size in response to temperature changes. In order to accomplish this, however, the ""238 patent discloses a very elaborate and thus relatively expensive storm shutter assembly. The ""921 patent discloses a corrugated sheet of plastic such as polycarbonate, that was made of material 0.062 to 0.125 thick about 13 inch wide. The ""921 patent shows a storm shutter that had to be put up in pieces and reinforced with aluminum or steel braces. This made the shutter very consumer unfriendly, and worse yet with the new building codes unable to pass the new impact standards.
A common problem shared by transparent storm shutters of the prior art is that in order to successfully pass the current missile impact test, like previously described, each plastic sheet is relatively thick, typically on the order of a 0.5 inch or more. with a jigsaw puzzle of reinforcement. Since impact plastics such as polycarbonate are relatively expensive and heavy, these designs cannot compete in the market. At other end of the spectrum are the thin lighter impact plastics such as corrugated polycarbonate reinforced with steel or aluminum braces that are consumer unfriendly and still can not pass the code mandated large missile impact test, thus become unmarketable.
Therefore, there is a need for a transparent storm shutter that is relatively inexpensive to manufacture, is compatible with current shutter systems, and is easy to install, yet capable of withstanding direct impacts from windborne debris during a storm.
The present invention is directed to a relatively inexpensive Combination Blade of extruded aluminum and transparent impact plastic such as polycarbonate, this Combination Blade is made to replace the metal blades currently used to manufacture accordion shutters. It is lightweight and of relatively simple construction, it is made with several hinge configurations so it can be used with many of the accordion shutters on the market today. It can be used to retrofit existing and/or make new accordion shutters. It is easy to install, yet capable of sufficiently resisting direct impacts from windborne debris during a storm.
The present invention is to be used with an accordion shutter assembly to protect glass windows and doors in homes, office buildings and other walled structures from the destructive force of storm systems, such as hurricanes. The present Combination Blade includes two mating hinges of aluminum assembled together with a flat sheet of transparent plastic, such as polycarbonate, that is held together with an urethane adhesive that actual forms a spline, giving it a mechanical and adhesive joint of unusual high strength due to the shape of the hinges. The present Combination Blade can then be assembled into an accordion shutter assembly, replacing all or some of the metal blades, using the same hex head bolts, flat washers, nylon bushings and roller assemblies normally used for assembling an accordion shutter assembly. The accordion shutter assembly is then firmly secured to a walled structure in the same manner as it always has been, the Combination Blade having no effect on the attachment.
In one embodiment of the present Combination Blade, it replaces a metal blade in an existing accordion shutter using the same hex head bolts, flat washers, nylon bushings, and roller assemblies and methods used to install a metal blade. In other embodiments, as will be discussed in greater detail hereafter, the Combination Blade can be used in the manufacturing of new accordion shutters, it can be used for all the blades to make a completely transparent shutter or in proportion to make a partially transparent window. This will give the building occupants, when a storm is imminent and the accordion shutters are closed, light inside and the ability to see the outside conditions. Still being secure by knowing flying debris will be deflected.
In embodiments where the Combination Blades are kept 8 inches or less in width, it has been found a much thinner sheet of transparent plastic can be used such as 0.093 polycarbonate sheet. In order to provide additional impact resistance against windborne debris there are serrations in the aluminum hinges that are filled with a urethane adhesive used to assembly the blade, that becomes a spline when hardened and adds a great deal of strength to the joints. The plastic such as polycarbonate being held on only two sides, contrary to prior art, defeats the chance of damage from thermal expansion and contraction. Further, because each Combination Blade has the exact hinge configuration as the all-metal blade it replaces, it needs no additional hardware, it mounts with the same hex head bolts, flat washers, nylon bushings, roller assemblies and methods used to mount a metal blade, making it easy to use with nothing new to learn, less elaborate, and less expensive making it much more consumer friendly than mounting systems used in prior transparent storm shutters.
To replace a metal blade with a Combination Blade the folding blade assembly of an accordion shutter assembly is removed from the assembly. Then the hex head bolts, flat washers, nylon bushings and roller assemblies are removed from the top and bottom of the existing blade, the blade is slid out and a Combination Blade is slid in its place, the hex head bolts, flat washers, nylon bushings and roller assemblies are replaced, then the folding blade assembly is replaced in the accordion shutter assembly.
It has also been found that an additional benefit of the particular construction of the present Combination Blade enables thinner sheets of transparent plastic material to be used while still providing a better degree of impact protection previously provided by thicker flat sheets of the same material.
Another objective of the present invention with aluminum hinges mounted on only two sides is to teach a plastic panel may be secured in place and not restrict the thermal expansion and contraction of the plastic sheets with no chance of damage.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof